I’ve had a few professors that you might consider inspiring but none that anyone would consider “nurturing” that I can recall. Nor would I want them to be nurturing. As an example, I am very, very thankful for the person I had as my PhD advisor, but he is very much a blunt, tells-it-like-it-is kind of person, and I think that, as a doctoral advisor, that’s a far superior quality. The entire point of a PhD (particukar in STEM fields where I have my experience) is to learn to become an independent researcher, and that means you need someone who is going to hold your feet to the flames and expect a lot of you, not someone who will coddle you.